Two of the most commonly used classifications for the posterior malleolus fracture are Haraguchi and Bartoníček. Both classifications are based on the morphology of the fracture. This study makes an inter- and intra-observer agreement analysis of the mentioned classifications. 39 patients with ankle fractures who met inclusion criteria were selected. All the fractures were analyzed and classified twice by each of the 20 observers using Bartoníček and Haraguchi's classifications, with a window period of at least 30days between the two rounds. Analysis was made by Kappa coefficient (ƙ). The global intraobserver value was ƙ = 0.627 in the Bartoníček classification and ƙ = 0.644 in the Haraguchi one. The first round global interobserver ƙ = 0.589 (0.574-0.604) on the Bartoníček classification and ƙ = 0.534 (0.517-0.551) on the Haraguchi one. Second round coefficients were ƙ = 0.601 (0.585-0.616) and ƙ = 0.536 (0.519-0.554), respectively. The best agreement was when there was involvement of the posteromedial malleolar zone with ƙ = 0.686 and ƙ = 0.687 in Haraguchi II and ƙ = 0.641 and ƙ = 0.719 in Bartoníček III. No differences were observed in Kappa values when an experience-based analysis was made. Bartoníček and Haraguchi classifications of the posterior malleolus fracture have both substantial intraobserver agreement but moderate to substantial agreement in interobserver analysis. IV.